Re: [syzbot] [PATCH] test uaf in sco_sock_timeout

[syzbot <syzbot+4c0d0c4cde787116d465@syzkaller.appspotmail.com>]

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***

Subject: [PATCH] test uaf in sco_sock_timeout
Author: lizhi.xu@windriver.com

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git 8de1e7afcc1c

diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index c736186aba26..515b52e14b5f 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -415,6 +415,8 @@ static void sco_sock_cleanup_listen(struct sock *parent)
  */
 static void sco_sock_kill(struct sock *sk)
 {
+	struct sco_conn *conn = container_of(sk, struct sco_conn, sk);
+
 	if (!sock_flag(sk, SOCK_ZAPPED) || sk->sk_socket)
 		return;
 
@@ -423,6 +425,9 @@ static void sco_sock_kill(struct sock *sk)
 	/* Kill poor orphan */
 	bt_sock_unlink(&sco_sk_list, sk);
 	sock_set_flag(sk, SOCK_DEAD);
+	sco_conn_lock(conn);
+	conn->sk = NULL;
+	sco_conn_unlock(conn);
 	sock_put(sk);
 }